The number of people in the air at any given time is astounding. According to the Federal Aviation Administration, more than 2.5 million passengers fly in and out of U.S. airports everyday. Worldwide, the number of travelers adds up to nearly 1 billion throughout the course of a year. Keeping those travelers comfortable, safe and on time is a huge undertaking.
Comfort levels are subjective and prompt arrivals depend on a variety of factors, but safety cannot be compromised. For all aerospace manufacturers, safety is the paramount goal.
In addition to meticulous designs and material selection, manufacturers must also have precise knowledge of the specific wear and performance characteristics of the materials they use in their aircraft. Safety starts in the design and manufacturing stages, but it continues all the way through the aircraft’s lifetime maintenance and repair requirements.
Since the first plane took flight more than 100 years ago, airplane manufacturing has evolved and improved and has ultimately become one of the most precise industries in the world. Building a plane requires precision to the tune of tolerances in the ten thousandths of an inch or tighter. With millions of airline passengers’ safety on the line, there can be no wiggle room.
Throughout the years, aerospace engineers have pinpointed a range of materials that deliver on performance, fuel efficiency and, above all else, safety. For many aerospace components, titanium, composites and aluminum are the materials of choice. They are widely accepted for a variety of material characteristics, including high stiffness, high strength, high toughness and low weight. These characteristics are also what make these materials difficult to work with.
Similarly, superalloys, such as Hastelloy, Inconel and other nickel-based materials, are found in various aerospace components, such as turbine blades, due to their superior mechanical strength and resistance to corrosion and oxidation. These materials, too, come with their own set of challenges.
Wear and tear
Over hundreds and thousands of hours in the air, planes experience wear and tear that must be addressed. The maintenance, repair and overhaul of civil and military aircraft requires a diverse range of processes. Pferd Inc., a developer and supplier of surface conditioning, deburring, and grinding products for aerospace component manufacturers in both commercial and defense industries, offers products for those processes that entail cutting, grinding, milling, filing, brushing and polishing as well as cleaning, deburring and producing defined surface finishes.
An example of one of the hundreds of parts that require maintenance attention is the high-pressure turbine (HPT) first-stage blade. Chad Waltemyer, national account manager, aerospace, at Pferd, says the turbine blade is one of the most important rotational components of an airplane engine. It’s also a part that experiences a significant level of wear – especially on the tips of the blades.
“It operates at high temperature and under conditions of extreme environmental attack, such as oxidation, corrosion and wear,” Waltemyer explains. “During the service and maintenance of an aerospace engine, the HPT first-stage blades, which are made of proprietary superalloys, suffer from increasing blade tip cracks after hundreds of hours in service.”
To address the cracks that appear in the turbine blade tips – due to the extreme nature of the heat generated by the engine – aerospace OEMs and their parts suppliers are taking advantage of Pferd’s carbide rotary burrs. These tools are used to open up the cracks that have formed so they can be tack welded and refilled with a blend of superalloy and brazed powders that are similar in chemistry to the original part material.
“These superalloys and brazed powders allow OEMs to repair the most intricate shapes, in the most demanding applications and parts, such as on the turbine blades and in an engine’s seal segments,” he says. “Just as innovation is key for the engineers producing these planes, innovation is also essential for the design and engineering of Pferd’s custom carbide burr tools, created specifically for exotic materials and applications.”
Pferd produces a standard line of carbide burrs designed for handling materials of virtually any strength. Made from tungsten carbide and with a proven shape and cut geometry, they offer concentricity and consistency. There are some instances, however, where a custom burr is required. Aerospace applications are a good example of that.
“Pferd offers the complete solution for repairing cracks with special carbide shapes in specialized cuts, including one for titanium,” Waltemyer says. “Standard options as well as custom offerings allow users to optimize the pneumatic tools that are being used with these products. Overall, the Pferd goal is to become the preferred solution provider by analyzing an OEM’s application and developing tailored solutions for them that increase productivity, lower overall manufacturing costs and keep passengers safe.”
Despite the custom and varying nature of the proprietary superalloys that are developed and employed by airplane manufacturers and their suppliers, Pferd is still able to produce incredibly effective solutions. This is possible thanks to the close relationships forged by Pferd and its customers and its collaborative approach to identifying the most effective solution to the customer’s requirements.
Be it a custom tool or one that’s off the shelf, Pferd partners with some of the biggest aerospace OEMs to ensure they are able to service and repair their aircraft regardless of challenging materials or applications. Here are just a few additional examples of how Pferd tools are used:
- Grinding radii on inner edges for seal segment repair or deburring turbine blades after grinding with PoliCap abrasive caps.
- Small diamond needle files ranging from 0.017 in. to 0.075 in. dia. are well-suited for work on the micro cooling holes found on large engine parts.
- Surface conditioning with Polinox cross buffs and carbide burrs on a variety of components.
- Cleaning and machining slots with a diamond grinding point.
- Deburring work on rotors, shrouds, hangers and turbine blades with M-Brad composite brushes.
In addition to these examples, Pferd boasts a full portfolio of products dedicated to aerospace maintenance and repair – both in the company’s standard line of offerings as well as its special, custom-designed products. Like its customers, Pferd understands and appreciates the attention to detail required to keep air travelers safe and, therefore, delivers the same level of care when producing its surface conditioning, deburring, and grinding products.